[Robotgroup] Menage aTux. Embedded Gnu/Linux Hardware Recommendation?

[brooksdesign]

 Ferrocement plotter?Got any pictures?Tell me more about that part.
   I toyed with that concept and want to try that with the gumbo machine tool I built.I have a 4'X4'X8'foot capacity on myXYZ table but still have no cnc drive controls yet but I do have at least access to the Sick DMEs that we use for the seat testers I work on here.
-brooks

-----Original Message-----
>From: Bruce Waters <biwaters at austin.rr.com>
>Sent: Feb 6, 2008 2:33 AM
>To: robotgroup at puremagic.com
>Subject: [Robotgroup] Menage aTux. Embedded Gnu/Linux Hardware	Recommendation?
>
>Rhett,
>  For my ferrocement plotter bots I am mixing/matching :
>1).wr850g's using OpenWrt Embedded Linux (just like 
>    Gray's well hacked wrt54g routers)
>     for 802.11g WiFi, 4 wired ethernet ports, plus 2 serial
>2).Vex controllers using Microchip mplib/C18 and WPIlib
>    for pwm servo/motor outputs, serial, and dido
>    There's no real OS here, just the Vex control processor.
>    Propeller's or basic stamps are alternatives to Vex.
>3).Sick DME 2000 laser rangefinder(s) 
>    for accurate positioning via serial (thence wr850g wifi)
>     These are normally >1K$ items but I bought some much
>     cheaper on Ebay and I love em.
>4).Many mongrel rebuilt $10/$20Goodwill scraptops 
>    (Compaq Presario 1200s, Gateway Solo 3350s, HP 
>     Pavilion N3410s,...) running Edubuntu Linux (some PXE) 
>     These scraptops provide USB, hdd, ethernet wired to wr850g, 
>     hi-res bot-mounted displays,  optical mice for super cheap 
>     closed control loops, serial to Vex,...
>5).Compaq DL380 dual processor server with 6X9GB scsi
>     raid, running Edubuntu with a PXE server for optional net 
>     boot of bot-mounted scraptop Edubuntu linux.
>     
>     Handheld "dashboard" Edubuntu Scraptops on my home 
>     lan (operating as remote operator consoles) communicate
>     to any bot-mounted scraptops through the command 
>    and control server.   Project design data resides on the
>    main ccs server, is translated to high level motion directives 
>    for specific plotterbots here and sent to plotterbot scraptops 
>    (over a wifi hop) which implement or delegate lower level 
>    motion directives with low-latency requirements(eg. to Vex)..
>
>I have wr850g routers I can spare for projects which could
>produce subsystems also useful for my purposes.  You might
>provide a wireless hop to the serial print head controller that
>Vern used in the ping pong ball printer with a couple of these
>routers.   Then anyone could mount the head on a mobile
>robot and print giant graphics on butcher paper taped to the
>floor without storing all that data on the mobile bot.    Two
>bots printing the same stream would document their relative
>positions in a time synchronized way so that what they did
>when could be reviewed afterwards for scoring contests or
>for teaching the physics of motion.   The botmounted router 
>could have a routine that would print the current value of 
>some keyword (myname=R0D0) when a symbolic for that 
>keyword appeared in the serial input stream . "My name is 
>$myname." might produce "My name is R0D0."  
>
>The wireless hop to the print head controller  idea is just an 
>example.  If you think of an application you would like to 
>implement, please describe it to me.  Perhaps we can get 
>multiple use of expended effort.  
>
>The five bullet description above is in various stages of 
>development.  I am a scheduling opportunist so I will not
>be publishing any dates for intended completion.  
>I obtained most of the hardware I have at a very low
>monetary cost relative to its actual value but with
>great effort expended at inconvenient times to get 
>those good values.   A great many of these items
>are rarely available at the prices I paid and some may
>be discontinued and may never be available again.
>It is therefore imprudent to assume that one can ever
>exactly replicate the things I create at reasonable cost.
>
>Luckily, most of the software I have used for this big
>project is (so far) publicly available on the web.
>Edubuntu Gutsy (7.10) is the workhorse and is
>very conveniently distributed.   Edubuntu is being
>massively distributed to K-12 users so its distribution
>has to be smooth and well tested.  There is an
>enormous set of applications also distributed with
>the Synaptic Package Manager so a great wealth
>of predominantly free software is available with
>fora and updates and large user communities.
>I think it is the way to go for a great many 
>purposes and I intend to use it whenever I
>possibly can.
>
>OpenWrt is a hacker beastie so it requires a great
>deal more sophistication but it is freely available
>on the web and my son did my router flashing so
>far.   Techie types can handle it reasonably easily.
>This long post essentially seconds the previous
>recommendation to use OpenWrt for embedded
>Linux.  I am just providing some detail to show
>how it might all fit into a productive environment.
>
>MPlab and the C18 and WPIlib are all free versions
>of software for Vex (it contains Microchip PICs) and 
>involve a somewhat complicated "tool chain". 
>Software development types can slog their way
>through these.  You can get fairly decent Vex
>function from a $200 EasyC Pro alternative which 
>might be easier to use for those who would rather 
>pay some money to avoid some of the complications
>of the free approach.   
>
>Using a simple control program and a little dedicated 
>hardware eliminates the extreme "need" get some 
>"real-time" version of Linux to deal with asynchronous, 
>high-speed-service-required, specifications.  Meeting 
>hardware requirements such as these is almost never 
>covered very well by an operating system which has 
>a myriad of other responsibilities.  Instead, dedicate 
>some hardware, dedicate some narrow purpose OS 
>(control pgm or a minimal real time Linux) and use 
>the usual general-purpose Linux like vanilla Edubuntu 
>at all but the lowest  levels of abstraction. 
>
>Bruce Waters
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